Abstract Three welding processes for aluminium parts have been considered for aircraft fabricatio... more Abstract Three welding processes for aluminium parts have been considered for aircraft fabrication: riveting, friction stir welding (FSW) and laser beam welding (LBW). These processes have advantages and threats, which were analysed in the present work focusing on T-pull and Hoop tensile properties. Concerning T-pull tests, LBW coupons presented higher ability to withstand the applied loads. This was due to the better distribution of loads when the strain is done in the stringer direction. In the case of the Hoop tests, which stress only the skin, the results obtained after FSW were notably higher in terms of ultimate tensile stress, yield stress and maximum strain. It was concluded that both LBW and FSW could replace riveting usually applied for commercial aircraft manufacturing.
The AISI 4340 steel has been largely employed for structural purposes, which requires resistance ... more The AISI 4340 steel has been largely employed for structural purposes, which requires resistance levels with yield strength above 1400 MPa and it attains high levels of resistance in dual phase, bainitic or martensitic microstructural conditions. The samples of AISI 4340 steel with different microstructural conditions (martensitic, bainitic and ferritic/perlitic) have been submitted to fatigue tests on push-pull mode. Subsequently, the new specimens underwent a shot peening surface treatment and new fatigue tests. The results have been discussed in comparison to the three microstructural conditions studied and they were related to a microstructural characterization. The results have showed that a shot peening treatment is not always beneficial to fatigue life, since there is a relationship between the compressive stresses developed on the surface and its roughness formed due to the deformations. Under the three microstructural above studied it was noticed a strong fatigue life reduction in the martensitic condition because such microstructure is considered less ductile.
Abstract Three welding processes for aluminium parts have been considered for aircraft fabricatio... more Abstract Three welding processes for aluminium parts have been considered for aircraft fabrication: riveting, friction stir welding (FSW) and laser beam welding (LBW). These processes have advantages and threats, which were analysed in the present work focusing on T-pull and Hoop tensile properties. Concerning T-pull tests, LBW coupons presented higher ability to withstand the applied loads. This was due to the better distribution of loads when the strain is done in the stringer direction. In the case of the Hoop tests, which stress only the skin, the results obtained after FSW were notably higher in terms of ultimate tensile stress, yield stress and maximum strain. It was concluded that both LBW and FSW could replace riveting usually applied for commercial aircraft manufacturing.
The AISI 4340 steel has been largely employed for structural purposes, which requires resistance ... more The AISI 4340 steel has been largely employed for structural purposes, which requires resistance levels with yield strength above 1400 MPa and it attains high levels of resistance in dual phase, bainitic or martensitic microstructural conditions. The samples of AISI 4340 steel with different microstructural conditions (martensitic, bainitic and ferritic/perlitic) have been submitted to fatigue tests on push-pull mode. Subsequently, the new specimens underwent a shot peening surface treatment and new fatigue tests. The results have been discussed in comparison to the three microstructural conditions studied and they were related to a microstructural characterization. The results have showed that a shot peening treatment is not always beneficial to fatigue life, since there is a relationship between the compressive stresses developed on the surface and its roughness formed due to the deformations. Under the three microstructural above studied it was noticed a strong fatigue life reduction in the martensitic condition because such microstructure is considered less ductile.
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Papers by Antonio Jorge Abdalla